The subject matter disclosed herein relates to a combined cycle power plant and, more particularly, to a heat recovery steam generator (HRSG) of a combined cycle power plant.
In a combined cycle power plant, a gas turbine engine generates power and electricity from the combustion of a mixture of fuel and air. The heat energy from this combustion is transmitted to a heat recovery steam generator (HRSG), which converts the heat into steam. The steam is then communicated to a steam turbine engine where additional power and electricity are produced.
When combined cycle power plants are deployed in the field, they are often run for certain periods of time when power demands on grids they supply are expected to be greatest. Once these periods end, the plants are shut down with the shut down process often requiring that the HRSG be purged of remaining fuel and air so that subsequent startups can be conducted safely. These purge events are conducted by running the gas turbine engine without combustion so that heated air is pumped through the HRSG. The purge events along with other similar events, such as forced cooling and gas turbine engine shut down events, can lead to condensation in the HRSG that can damage various components within the HRSG and cause potentially premature failure.